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Blood glucose testing
Maggie, a 3 year old Labrador Retriever with diabetes. The video shows Maggie having her blood glucose checked at home using one of the "lip stick" methods of testing. Many caregivers with diabetic pets test their pets' blood glucose at home using a glucometer. Home blood glucose monitoring is extremely beneficial for reasons of safety, better regulation and lower cost. Testing blood glucose in a dog requires a bit of practice, but those who persevere master the skill eventually. Reasons for Home Testing Monitoring your pet's blood glucose concentration at home has many benefits and is increasingly recommended by veterinarians, especially those who specialize in diabetes. Dr. Sara Ford made a presentation about the need for home blood glucose testing at the 2010 AVMA Convention, saying, ""If you're a human diabetic you monitor your blood sugar between 4-6 times a day." I believe that state-of-the-art care in veterinary medicine in 2010 includes home blood-glucose monitoring." Dr. Ford believes testing should be done at least twice a day. When to test The tests are done at least once before each insulin shot, and sometimes once more a day, about halfway between shot times, generally at the expected time of peak insulin action. While adjusting dosage, that third peak reading is vital -- the rest of the time it's just a good check once in a while. Note that the expected peak time varies by case, you'll need to determine your pet's peak time first, using some blood glucose curves. Curves are usually done on weekends or days off. Where to test Some people think they will have to draw blood from one of the animal's veins to test the blood glucose level. This obviously isn't so. You're testing in the same manner as people with diabetes--by drawing a small amount of blood with a lancet, just as they do. Much is said (and shown in some videos) about earflap testing, but most people who do blood testing seem to find more success using other areas. There's no preferred place to test from the list above; the one that works for you and your pet is the right one for you. You may need to experiment with testing in the various spots until you find the one. Venous vs Capillary Blood In 2002, a study was done with blood samples taken by the "ear nick" technique (drawing capillary blood for testing) and blood obtained by the traditional venipuncture method, comparing samples from both diabetic and non-diabetic cats. The non-diabetic cats' blood results with the ear nick test was not found to be significantly different from the blood testing using venous blood. For those with diabetes, the results regarding ear nick vs venipuncture was found to be significantly different, but the difference was not found to be clinically important. The conclusion drawn by the study indicates that drawing capillary blood is a reasonable alternative to drawing blood from a vein. Blood glucose testing vs urine glucose testing Some reasons for preferring testing glucose levels by using blood over urine testing is that the urine used in testing may have been in the bladder for hours. Because of this, it may not be a reliable indicator of what systemic glucose levels are at the time of testing. What's seen when testing urine for glucose is an average of what the level of glucose has been over a period of about 5-8 hours (the time period from last urination). Urine testing also makes it more difficult to determine whether any hyperglycemia noted is the result of a Somogyi rebound pattern or a true need for an increase in insulin dosage. Urine only tests positive for glucose when the renal threshold has been exceeded for a length of time. There also must be some degree of glycosuria (glucose in urine) present in order for a urine test to detect development of hypoglycemia. With urine testing for glucose, getting a negative result means your pet is somewhere under the Renal threshold of 180 mg/dl or 10 mmol. Glucose doesn't spill into the urine until at or above that point. This could mean he/she is in the euglycemic zone where all's well or that the dog is headed for the hypoglycemic one. Knowing that the pet's blood glucose levels are too low means that you can take action with a sugar source or some food to ward off a possible hypo episode. Factors Which Can Affect Readings Common Problems with Meters and Readings Why you still need Ketostix/Ketodiastix While home testing blood with a meter can tell you what your pet's blood glucose levels are, most can't do blood ketone testing. When you have high blood glucose levels, doing ketone testing with Ketodiastix or Ketostix is good practice to make sure your pet doesn't have ketones. Good BG Readings but Positive Ketone Results When the bg readings are high enough to produce some ketones, you've taken action to bring them down and they are normal once more, it is possible to still see some positive urine ketone test results. Ketones show up in the urine right away. When you're getting normal bg readings, it means that there are no more ketones being produced. What you are seeing when you test urine for ketones and the blood glucose is in normal ranges are the "leftovers" of the ketones which were produced by the high bg episode. They will continue to show up in the urine for a while but their concentration will become less and less until they're gone. How to test These sites contain helpful information about hometesting with pictures and sometimes videos. *Earflap Method for Testing Blood-Dogs *Photos and information for using various testing sites Online Videos *Page with hometesting video links-K9diabetes.com *AlphaTrak Obtaining a Blood Sample Video *VetRxSupply-iPet Meter Video shows paw testing for dogs Hometesting Misconceptions Some vets discourage home blood testing on various pretexts. These DVMNews articles and this Canadian Veterinary Journal (CVJ) may be helpful in convincing them otherwise. Vets themselves use hand-held glucometers for a number of illness other than diabetes itself; both sepsis and insulinomas (insulin-producing tumors) cause hypoglycemia. The patients need not be diabetic to have hypoglycemia from these conditions. Vets sometimes discourage hometesting saying that it will spook the pets, making them wary of their caregivers, or could cause testing site infections. Again this turns out not to be the case. Most pets are amenable to the test once they become accustomed to the routine (petting and a treat at test time help). Concerns about test site infections can be alleviated by using hydrogen peroxide or an antibacterial ointment on the site after the test. A study performed with diabetic dogs and their caregivers indicated that 85% of those new to home testing/monitoring of blood glucose were able to succeed and continue doing so with little to no problems. Vets also sometimes discourage hometesting saying that the caregiver will become too focused on the numbers, rather than the overall condition of the pet. While the pet's overall condition is indeed an important consideration in evaluating and treating its diabetes, blood glucose readings are critical to regulating the pet and to avoiding hypoglycemia, which is caused by injecting more insulin than the pet needs at the time. No single blood-glucose reading, whether at a vet or at home, is adequate for determining a correct insulin dosage. The first few months can be especially tricky while finding a correct dose, and there are no substitutes for frequent testing and occasional curve-plotting. These tests are best performed at home, both because vet stress causes inaccurate readings, and because you can test more frequently and regularly at home. Some other reasons for preferring testing glucose levels by using blood over urine testing is that the urine used in testing may have been in the bladder for hours. Because of this, it may not be a reliable indicator of what systemic glucose levels are at the time of testing. What's seen when testing urine for glucose is an average of what the level of glucose has been over a period of about 5-8 hours (the time period from last urination. Urine testing also makes it more difficult to determine whether any hyperglycemia noted is the result of a Somogyi rebound pattern or a true need for an increase in insulin dosage. There also must be some degree of glycosuria (glucose in urine) present in order for a urine test to detect development of hypoglycemia). You may see that blood drawn when glucose levels are normal is has a lighter color then when they are high. This is due to an enzyme (glucose oxidase) in the strip reacting to the amount of glucose in the blood. References More Information *Home Monitoring of Blood Glucose Concentration by Owners of Diabetic Dogs Reusch, et. al.-Journal of Small Animal Practice-2003 *Blood Glucose Testing-Dogs BD Diabetes * Capillary blood collection valuable tool in at-home diabetes management Ford, Sara, 2002, DVM Newsmagazine * Monitoring and treatment of the diabetic cat Reusch, C. E., 2005, Proceedings of ECVIM-CA 15th Annual Congress. * Capillary blood sampling from the ear of dogs and cats and use of portable meters to measure glucose concentration Wess G, Reusch C, 2000, Journal of Small Animal Practice * Experiences with Blood Glucose Home Monitoring by Owners of Diabetic Dogs and Cats Reusch, Claudia, 2002, WSAVA * Choosing a Glucometer Pet Diabetes.org * Freestyle meters read a bit low as numbers get higher *Monitoring Diabetes in Dogs & CatsNelson, Richard, 2003, WSAVA Note: Dr. Nelson is a VERY well-known expert on animal diabetes; his presentation supports hometesting. *Retrospective Study of Owners’ Perception on Home Monitoring of Blood Glucose in Diabetic Dogs and Cats Van de Maele, I., et. al. 2005, Canadian Veterinary Journal *Home Monitoring of Blood Glucose in Diabetic Patients North American Veterinary Conference-2006 *Checking a Ferret's Blood Sugar Using the Freestyle Glucometer *Monitoring of Glycemia in Dogs & Cats with Diabetes Mellitus-Page 36 Reusch, Claudia, 2006, OSU Endocrinology Symposium *How home blood and urine tests measure blood glucose Wikipedia *Regulating Insulin Richards, Mike, VetInfo4Dogs Category:Tips Category:Regulation Category:Introduction Category:Treatments Category:Terms Category:Content Category:Tests